LAN Switch Security: What Hackers Know About Your Switches

LAN Switch Security: What Hackers Know About Your Switches

A practical guide to hardening Layer 2 devices and stopping campus network attacks

Eric Vyncke
Christopher Paggen, CCIE® No. 2659

Contrary to popular belief, Ethernet switches are not inherently secure. Security vulnerabilities in Ethernet switches are multiple: from the switch implementation, to control plane protocols (Spanning Tree Protocol [STP], Cisco® Discovery Protocol [CDP], and so on) and data plane protocols, such as Address Routing Protocol (ARP) or Dynamic Host Configuration Protocol (DHCP). LAN Switch Security explains all the vulnerabilities in a network infrastructure related to Ethernet switches. Further, this book shows you how to configure a switch to prevent or to mitigate attacks based on those vulnerabilities. This book also includes a section on how to use an Ethernet switch to increase the security of a network and prevent future attacks.

Divided into four parts, LAN Switch Security provides you with steps you can take to ensure the integrity of both voice and data traffic traveling over Layer 2 devices. Part I covers vulnerabilities in Layer 2 protocols and how to configure switches to prevent attacks against those vulnerabilities. Part II addresses denial-of-service (DoS) attacks on an Ethernet switch and shows how those attacks can be mitigated. Part III shows how a switch can actually augment the security of a network through the utilization of wirespeed access control list (ACL) processing and IEEE 802.1x for user authentication and authorization. Part IV examines future developments from the LinkSec working group at the IEEE. For all parts, most of the content is vendor independent and is useful for all network architects deploying Ethernet switches.

After reading this book, you will have an in-depth understanding of LAN security and be prepared to plug the security holes that exist in a great number of campus networks.

Eric Vyncke has a master’s degree in computer science engineering from the University of Liège in Belgium. Since 1997, Eric has worked as a Distinguished Consulting Engineer for Cisco, where he is a technical consultant for security covering Europe. His area of expertise for 20 years has been mainly security from Layer 2 to applications. He is also guest professor at Belgian universities for security seminars.

Christopher Paggen, CCIE® No. 2659, obtained a degree in computer science from IESSL in Liège (Belgium) and a master’s degree in economics from University of Mons-Hainaut (UMH) in Belgium. He has been with Cisco since 1996 where he has held various positions in the fields of LAN switching and security, either as pre-sales support, post-sales support, network design engineer, or technical advisor to various engineering teams. Christopher is a frequent speaker at events, such as Networkers, and has filed several U.S. patents in the security area.

Contributing Authors:
Jason Frazier is a technical leader in the Technology Systems Engineering group for Cisco.
Steinthor Bjarnason is a consulting engineer for Cisco.
Ken Hook is a switch security solution manager for Cisco.
Rajesh Bhandari is a technical leader and a network security solutions architect for Cisco.

Use port security to protect against CAM attacks
Prevent spanning-tree attacks
Isolate VLANs with proper configuration techniques
Protect against rogue DHCP servers
Block ARP snooping
Prevent IPv6 neighbor discovery and router solicitation exploitation
Identify Power over Ethernet vulnerabilities
Mitigate risks from HSRP and VRPP
Stop information leaks with CDP, PaGP, VTP, CGMP and other Cisco ancillary protocols
Understand and prevent DoS attacks against switches
Enforce simple wirespeed security policies with ACLs
Implement user authentication on a port base with IEEE 802.1x
Use new IEEE protocols to encrypt all Ethernet frames at wirespeed.

This security book is part of the Cisco Press® Networking Technology Series. Security titles from Cisco Press help